Fast Detection of Single Liposomes Using a Combined Nanopore Microelectrode Sensor

Area of Science:

• Electrochemistry
• Nanotechnology
• Biophysics

Background:

• Liposomes are crucial for drug delivery and biological signaling.
• Sensing individual liposomes and their contents is challenging.
• Existing methods lack high-throughput capabilities for real-time analysis.

Purpose of the Study:

• To develop and characterize a novel high-throughput sensing device for single liposome detection.
• To investigate the mechanism of liposome disruption and content release during translocation.
• To assess the utility of the device for analyzing liposomal formulations and biological vesicles.

Main Methods:

• Utilized a quartz nanopipette positioned near a carbon-fiber microelectrode (CFE).
• Employed resistive-pulse analysis for detecting liposomes based on ionic current changes.
• Collected simultaneous redox signals from released liposome contents at the CFE.

Main Results:

• Observed coincident redox signals and resistive pulses, indicating content leakage during translocation.
• Determined that liposome disruption occurs at the nanopore orifice, independent of the electric field.
• Found that disruption probability depends on fluid flow velocity and nanopore geometry.

Conclusions:

• The developed device enables high-throughput, single liposome analysis.
• Liposome content release is linked to translocation dynamics and nanopore characteristics.
• This technique offers potential for rapid analysis of drug formulations and neurotransmitter release from vesicles.